But because they're virtually all illegal in the UK for most people, it's not only hard for patients to experience it but also for researchers to see what else cannabis can do.
One mother is planning on defying British law when she flies from Canada to London with a package of medical cannabis for her son, Billy.
The 12-year-old was the first in the UK to receive a consignment of the drug on the NHS to help him with his intractable epilepsy, where he suffered up to 100 seizures a day. His mum, Charlotte Caldwell says the medical cannabis virtually cured Billy's symptoms and improved his quality of life.
Credit: Facebook/Keep Billy Alive
But according to Charlotte, the Home Office told their family doctor to stop handing out the life-saving treatment.
So she flew to Canada, where the drug is legal, to stock up on the medicine before Billy's ran out.
Charlotte fully plans to declare the cannabis when she arrives, knowing full well it will create a bit of a nightmare at customs.
She's told the Daily Mail: "Of course I worry about breaking the law - but I want my son illegally alive rather than legally dead.
"I will ask them if they will let me keep this safe, regulated medicine that has kept my little boy alive - or are they going to take it off me, condemning my son to possible death?
"If they confiscate Billy's medicine and arrest me, they are signing his death warrant."
Safe to say it will be a tough decision for the Customs officials.
The drug prescribed for Billy in Canada has a very high ratio of CBD to THC, the former is the non-psychoactive chemical in cannabis versus the latter which is what gets you high.
Billy's GP, who wished to remain anonymous, told the MailOnline: "The debate on cannabis is so muddled - this is not recreational cannabis but a safe, regulated drug. And this is not just for Billy. There are 240 other children in Northern Ireland alone who suffer intractable epilepsy.
"Can you imagine how cruel it is to see children having these seizures knowing there is a drug that could help but they are not allowed it? We have to find a solution."
The Home Office says that while it sympathises with Billy's situation, it has a commitment to only support drugs that are 'thoroughly tested'.
Featured Image Credit: Facebook/Keep Billy Alive